Kelly 60CT Diamond Harrow V 1 for LS 17 by FS 2017 mods · April 7, 2017 Kelly 60CT Diamond Harrow V 1 for LS 17 Today we present you the Kelly Diamond Harrow. This 60ft. (18m) wide disc harrow covers alot of ground in a short period of time. It’s fastest working speed is 18km/h (12miles/h). This is a great tool for preparing the soil ahead of planting. Warning though, you’ll need quite a large tractor to pull it, as it is horsepower hungry. It also works with stumble cultivator. Enjoy!